diff options
| -rw-r--r-- | lib/VMCore/ConstantFold.cpp | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp index a7662fd..c950e8d 100644 --- a/lib/VMCore/ConstantFold.cpp +++ b/lib/VMCore/ConstantFold.cpp @@ -1427,7 +1427,7 @@ Constant *llvm::ConstantFoldGetElementPtr(const Constant *C, // long 0, long 0) // To: int* getelementptr ([3 x int]* %X, long 0, long 0) // - if (CE->isCast() && NumIdx > 1 && Idx0->isNullValue()) + if (CE->isCast() && NumIdx > 1 && Idx0->isNullValue()) { if (const PointerType *SPT = dyn_cast<PointerType>(CE->getOperand(0)->getType())) if (const ArrayType *SAT = dyn_cast<ArrayType>(SPT->getElementType())) @@ -1436,6 +1436,28 @@ Constant *llvm::ConstantFoldGetElementPtr(const Constant *C, if (CAT->getElementType() == SAT->getElementType()) return ConstantExpr::getGetElementPtr( (Constant*)CE->getOperand(0), Idxs, NumIdx); + } + + // Fold: getelementptr (i8* inttoptr (i64 1 to i8*), i32 -1) + // Into: inttoptr (i64 0 to i8*) + // This happens with pointers to member functions in C++. + if (CE->getOpcode() == Instruction::IntToPtr && NumIdx == 1 && + isa<ConstantInt>(CE->getOperand(0)) && isa<ConstantInt>(Idxs[0]) && + cast<PointerType>(CE->getType())->getElementType() == Type::Int8Ty) { + Constant *Base = CE->getOperand(0); + Constant *Offset = Idxs[0]; + + // Convert the smaller integer to the larger type. + if (Offset->getType()->getPrimitiveSizeInBits() < + Base->getType()->getPrimitiveSizeInBits()) + Offset = ConstantExpr::getSExt(Offset, Base->getType()); + else if (Base->getType()->getPrimitiveSizeInBits() < + Offset->getType()->getPrimitiveSizeInBits()) + Base = ConstantExpr::getZExt(Base, Base->getType()); + + Base = ConstantExpr::getAdd(Base, Offset); + return ConstantExpr::getIntToPtr(Base, CE->getType()); + } } return 0; } |